How about low light AF?
If you go for sigma - buy new (and that comes from somebody who buys 90% gear 2nd hand)
The problem with sigma is a very high chance of getting focus problems)
A very high chance - really?
My own Siggy was written off as a hopeless pile of poo by someone who I could clearly see was nodding forward or backward after he'd half pressed the shutter button and you just can't do that and expect to hit focus with a f1.4. You can't hold Siggy responsible for poor technique.
Well, this thread has made my mind up. Sigma it is. Fed up with focus issues with nifty fifty.
The Sigma F1.4 is designed to give the best possible performance at F1.4



Probably true. People who don't have problems generally don't post reviews so I think you do need to take this with a pinch of salt.Well, at least we have a very high chance of reading about a very high chance of focus issues in internet forums.
I still don't believe it.
'The Sigma F1.4 is designed to give the best possible performance at F1.4'Dunno where you've got that from but I don't believe it.
It's not razor sharp wide open although by all accounts it's better than the Canon. According to reviews it actually hits max sharpness at f4-5.6 and I think I'd agree with that.
'The Sigma F1.4 is designed to give the best possible performance at F1.4'
If it wasn't designed to give the best possible performance that they could offer in that price range, then why would they even bother producing it?QUOTE]
I have the Siggy and it's actually relatively soft at f1.4. It may be better than much older 50mm designs like the Canon but it isn't as sharp as Sigma's own 30mm, which I also own, at f1.4. I therefore don't really believe that Sigma set out to do the best possible job they could with this lens at f1.4 as at least one of their own lenses shows that they can design a lens to be sharper at f1.4. As for why Siggy have produced the lens, from what I've read they're designed it with a different design philosophy than that used with for example the older Canon and traditional German designs and to have better central performance rather than across the frame.
Some on line reviews seem to say the same thing as me about performance at f1.4 so I suppose it's up to each of us to make our minds up if this lens is for us. I love mine but I won't claim that it's razor sharp at f1.4 because it isn't, not when pixel peeping anyway. It may be sharp for a 50mm at f1.4 and better than the Canon but I've never used that.